The following was presented at the 2010 American Bee Research Conference in Orlando, FL.
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Kim Stoner presents: PESTICIDE IN POLLEN TRAPPED FROM HONEY BEE HIVES IN CONNECTICUT – TWO YEARS OF RESULTS IN RELATION TO ACUTE TOXICITY DATA. American Bee Research Conference. Orlando, Fl. January 15th, 2010.
30. Stoner, K.A. & B.D. Eitzer – PESTICIDE IN POLLEN TRAPPED FROM HONEY BEE HIVES IN CONNECTICUT – TWO YEARS OF RESULTS IN RELATION TO ACUTE TOXICITY DATA - In two years of measuring pesticides in trapped pollen from healthy hives in 3-4 locations around Connecticut, the authors found residues of 44 pesticides and pesticide metabolites. As a very rough first step in evaluating the significance of the concentrations of these pesticides in pollen, we gathered the available data on the contact and oral lethal doses that would kill 50 % of the tested population (LD50) of these pesticides from the U.S. Environmental Protection Agency and Agritox (France1) databases. Note that LD50 is typically measured with a single dose, evaluated over 24 -48 hours (U.S. EPA 19962). Not all of the pesticides found have acute toxicity data in these databases, including the most commonly detected pesticide, coumaphos.
In order to calculate a dose in micrograms per bee from the concentration data, we used the calculation of Rortais et al. (2005 Apidologie 36:71-83) that an adult worker bee would consume 65 mg of pollen, on average, during a period of 10 days as a nurse bee.
Using this calculation for the concentration of each pesticide found in a trapped pollen sample (mixed pollen collected over 3-4 days), we found only one sample in 2007 where the dose of pesticide was calculated to be over the oral LD50 – a sample with imidacloprid measured at 70 ppb, which calculates to 123% the oral LD50 from the Agritox database. Pesticides with residues over 10% of the contact or oral LD50 are given in the Table.
1Agence Française de Sécurité Sanitaire des Aliments (AFSSA). 2009. Agritox database. Base de données sur les substances actives phytopharmaceutiques. http://www.dive.afssa.fr/agritox/php/fiches.php
2 Ecological Effects Test Guidelines. OPPTS 850.3020. Honey Bee Acute Contact Toxicity. http://www.epa.gov/opptsfrs/publications/OPPTS_Harmonized/850_Ecological_Effects_Test_Guidelines/Drafts/850-3030.pdf
Table – Pesticide residues found in pollen that met or exceeded the contact or oral LD50.
Pesticide |
Maximum residue in a sample (ppb) |
Calculated dose to a nurse bee (µg/bee) |
% of contact LD 50 |
% of oral LD 50 |
|
Imidacloprid (2007) |
70 |
0.0046 |
10% |
123% |
|
Imidacloprid (2008) |
23 |
0.0015 |
3.4% |
40% |
Chlorpyrifos |
25 |
0.0016 |
16% |
1.5% |
Phosmet |
3720 |
0.242 |
23% |
No LD 50 |
More presentations from this conference can be found at Proceedings of the American Bee Research Conference 2010
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